When I came to London to do a BBC documentary, Under London. We discovered an atomic-bomb shelter under High Holborn, fish cellars in Billingsgate and a place under the Thames where slaves were kept 300 years ago.

What do you miss when you're not in London?

Now and again, I miss the bustle and colour that were the original reasons we left the city.

What are your favourite home comforts?

Hot baths with Radox when I return cold and muddy from a two-hour run on the moor.

What are your extravagances?

My two Land Rovers. My Defender is for rough farm work and my top-of-the-range Discovery for off-road adventures and long motorway journeys.

What would you do if you were Mayor for a day?

I'd increase the litter penalty and the policing of littering. It's shameful some boroughs are ruined by it.

What is your life philosophy?

Try and listen more than you talk. The creator designed us with two ears and only one tongue.

What were the last books you bought?

The Harry Potter books for my godchildren and nieces. I'm not a fan, but my great-nephew Joe auditioned for Harry so I feel a sort of connection.

What was the last CD you bought?

The soundtrack of The Phantom of the Opera.

Do you have a favourite pub?

When I was organising the first round-the-world trek via the poles in the Seventies, the team was based in the King's Road barracks. We'd go to the Cross Keys in the evenings.

What were your most memorable meals?

Harrods Food Halls always make me happy. I'll never forget my last meal in Cape Town before spending 18 months eating dehydrated food during the first one-way-only crossing of Antarctica. …